The fundamental data types, namely char int, float, and double are used to store only one value at any given time.  Hence these fundamental data types can handle limited amounts of data. 

In some cases we need to handle large volume of data in terms of reading, processing and printing. To process such large amounts of data, we need a powerful data type that would facilitate efficient storing, accessing and manipulation of data items. For example: If the user wants to store marks of 100 students. This can be done by creating 100 variables individually but, this process is rather tedious and impracticable. This type of problem can be handled in C programming using arrays.

C Array is a collection of variables belongings to the same data type. You can store group of data of same data type in an array.

                                                      (Or)

An array is collection of homogeneous elements in a single variable. 

• Array might be belonging to any of the data types

• Array size must be a constant value.

• Always, adjacent memory locations are used to store array elements in memory.

• Individual values are called as elements. 

• It allocates sequential memory locations.

We can use arrays to represent not only simple lists of values but also tables of data in two or three or more dimensions.  

• One–dimensional arrays 

• Two–dimensional arrays 

• Multi-dimensional arrays